This invention relates to an antiskid apparatus for automotive vehicles.
An example of a conventional antiskid apparatus for automotive vehicles is disclosed in the specification of Japanese Patent Publication (KOKOKU) No. 49-28307.
As shown in FIG. 6, the conventional antiskid apparatus has an inlet solenoid valve 3 arranged between a master cylinder 1 and a wheel brake 2, and an outlet solenoid valve 5 arranged between the wheel brake 2 and a reservoir 4. A pump 6 is arranged between the reservoir 4 and the master cylinder 1 and the circuit arrangement is such that a working fluid discharge from the pump 6 circulates to the master cylinder 1 and inlet solenoid 3.
Thus, the circuit arrangement is such that the working fluid is circulated between the master cylinder 1 and inlet solenoid 3 in the conventional antiskid apparatus. Consequently, when the inlet solenoid valve 3 is closed at operation of the antiskid function, the fluid pressure increases between the inlet solenoid valve 3 and pump 6, and this pressure is applied directly to the master cylinder 1, as a result of which the brake pedal 7 is forced backward. When the inlet solenoid valve 3 is opened, there is a decrease in the fluid pressure between the inlet solenoid valve 3 and the pump 6, so that the pedal 7 is drawn inward. Owing to repeated opening and closing of the inlet solenoid valve 3 at high speed when the antiskid operation is in effect, the pedal 7 is caused to undergo considerable vibration and the driver is subjected to discomfort as a result. If this pedal shock were to be completely eliminated, however, the driver would no longer be able to feel the antiskid action.